GRDC-Caravan: extending Caravan with data from the Global Runoff Data Centre

Abstract. Large-sample datasets are essential in hydrological science to support modelling studies and advance process understanding. Here, we present the GRDC-Caravan dataset, an extension to the large-sample hydrology project Caravan. Caravan is a community initiative which aims to combine large-sample hydrology datasets of meteorological forcing data, catchment attributes and discharge data for catchments around the world. The GRDC-Caravan extension is based on a subset of hydrological discharge data and station-based watersheds from the Global Runoff Data Centre (GRDC), which are covered by an open data policy. The GRDC is an international data centre operating under the auspices of the World Meteorological Organization (WMO), which collects quality-controlled river discharge data and associated metadata from the National Meteorological and Hydrological Services (NMHS) of WMO member states. The extension contains discharge data and catchment boundaries from GRDC, which can be released under a permissive license (CC-BY-4.0). In addition, the extension contains meteorological forcing data and catchment attributes from the global datasets ERA5-Land and HydroATLAS in a standardized format. The dataset covers stations from 5356 catchments and 25 countries and spans the years 1950–2023. Compared to the core version of Caravan, the extension takes the total number of Caravan catchments to be 22 372 (of which 1589 catchments are duplicates between the core and extensions). While in the core Caravan dataset mostly stations from North America, central Europe and South America were included, the new extension significantly improves the global coverage of the dataset with new stations across Europe, South America, South Africa, Australia and Aotearoa New Zealand. In addition, the temporal extension of the time series could be significantly increased from 40–70 years. The extension strongly improves the global and temporal coverage of Caravan and represents a valuable dataset for global hydrological and climatological modelling studies. The dataset is released under a CC-BY-4.0 license that allows for redistribution and is publicly available on Zenodo: https://doi.org/10.5281/zenodo.15349031 (Färber et al., 2025).